EQUITY OF AMERICAN ASSETS TRUST, INC. - ATM Equity Program (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Equity [Line Items]
Proceeds, net	$ 10,272	$ 46,926
At The Market Equity Program
Equity [Line Items]
Number of shares of common stock issued through ATM program	53,800
Weighted average price per share	$ 42.54
Proceeds, gross	2,288
Proceeds, net	2,164
Commissions | At The Market Equity Program
Equity [Line Items]
Payments of stock issuance costs	(23)
Other Offering Costs | At The Market Equity Program
Equity [Line Items]
Payments of stock issuance costs	$ (101)